1. Field of the Invention
This invention relates to a device for and a method of unwrapping conducting cables that have become entangled due to the wind, weather or cable breakage. More particularly, this device is directed at unwrapping energized, high voltage conductors in rough, mountainous terrain.
2. Description of the Prior Art
High voltage conductors are often suspended through rough, mountainous terrain, where the distance between towers can reach and exceed 3600 feet. Along these spans, the conductors are often subjected to high winds that cause conductor movement, which is sometimes considerable. The conductors are generally organized in a bundle, which can be configured as two parallel subconductors, a triangular arrangement of subconductors or a square or quad arrangement.
Due to the stresses imparted to the conductors by severe conditions, such as high winds, the spacers that separate the subconductors can break. When such breakage of spacers occurs, it is possible for the subconductors to become entangled or wrapped around one another. If such a condition is not rectified immediately, the conductors can be damaged mechanically, thus causing a conductor failure. A conductor failure can lead to a series of tower failures, as the towers which support such long spans of conductors are not constructed to tolerate conductor failures. This can lead to power outages or interruptions in power supply. Because people and industries depend on the continuous supply of power, it is desirable to avoid power interruptions, and especially desirable to avoid prolonged power outages.
Known methods of disentangling the subconductors involve the use of getting a bucket truck or crane to the tangled subconductors so that a utility worker can service the conductors. However, this method of untangling conductors is often difficult because, as mentioned above, the spans of the conductors often exceed 3600 feet. Sometimes these spans go over lakes, rivers or mountain ravines. It is nearly impossible to get a utility worker in a bucket to such positions.
No known prior art is directed to a solution for such a problem. However, multiple cable blocks, such as that disclosed in U.S. Pat. No. 3,819,154 to Miller are known. Multiple cable blocks are used to string a number of aerial cables at the same time. Such a cable block is directed at stringing telephone, CATV or the like. However, such cable blocks do not contemplate use with high voltage power lines, which can carry 100 kV or more. The rollers used in the cable block of Miller each support a cable 54 as illustrated in FIG. 9 of that patent. There is no provision for any mechanism for trapping the subconductors or cables between rollers or sheaves.
Two patents to Highland, U.S. Pat. No. 3,702,124 and U.S. Pat. No. 4,163,480, are directed to line travelling skips. However, such a device is meant only to carry utility workers along power lines and to skip over hardware attached to the line. These skips do not contemplate capturing tangled subconductors and unravelling them.